Magnetic toy construction modules with side-mounted magnets

ABSTRACT

Three-dimensional assemblies include substantially planar structural components having various two-dimensional generally polygonal shapes. Each such structural component includes a plurality of magnets positioned substantially at the midpoints of the polygonal sides of the structural component for use in connecting multiple instances of such structural components together, e.g., via the use of interconnecting ferromagnetic balls sized and configured for efficient interaction with such magnets. Such structural components can also include one or more slots extending inward from the peripheral edge surface of the component for use in assembling corresponding structural components together in an interlocking fashion, e.g., to form cruciform.

This application claims the benefit of U.S. Provisional Application No. 60/634,942, filed Dec. 10, 2004, which is herein incorporated by reference in its entirety.

BACKGROUND

1. Field of the Invention

The present invention is directed generally to puzzles and toys. More particularly, the present invention is directed to structural components having magnetic surfaces and which can be magnetically and/or mechanically coupled to form three-dimensional assemblies.

2. Background of the Invention

Individuals often find enjoyment in the challenge of building aesthetic structural designs and/or functional structural models. Frequently, the utility associated with constructing such structures is found in the creative and/or problem solving process required to achieve a desired structural objective. Currently, construction assemblies that exploit magnetic properties to interlink various structural components and thereby form different two and/or three dimensional structures are known and can provide an added dimension of sophistication to the construction process (see, for example, the magnetic construction toy disclosed in Balanchi U.S. Pat. No. 6,626,727, the modular assemblies disclosed in Vicentielli U.S. Pat. No. 6,566,992, and the magnetic puzzle/toy disclosed in Smith U.S. Pat. No. 5,411,262). In addition, German Patent No. DE 202 02 183 U1 to Kretzschmar describes flat triangles, squares and rectangles used in conjunction with ferromagnetic balls to create a limited range of geometric constructions. The flat shapes disclosed in the Kretzschmar German Patent consist of magnets inserted in the corners of a triangular or square piece, or six magnets in a rectangular plate which can be attached to steel balls to create a limited number of three-dimensional shapes. Thus, conventional construction kits are appealing to persons of all ages in that they allow for both aesthetic and geometric creativity.

The above-noted magnet construction assemblies each contain a certain number of component parts, which can sometimes limit geometries and stable or secure connections. Thus, a need remains for a magnetic construction assembly that provides more flexibility in both aesthetic and geometric design, and, moreover, that provides an additional degree of design/construction sophistication.

BRIEF SUMMARY OF THE INVENTION

In accordance with the present invention, substantially planar structural components are provided having various two-dimensional generally polygonal shapes, such as squares and triangles. Each such structural component is sized for easy manipulation and includes a plurality of externally-oriented edge-mounted magnets positioned substantially at the midpoints of the polygonal sides of the structural component for use in connecting multiple instances of such structural components together, e.g., via the use of interconnecting ferromagnetic balls sized and configured for efficient interaction with such magnets. Such structural components can also include one or more slots extending inward from the peripheral edge surface of the component for use in assembling corresponding structural components together in an interlocking fashion, e.g., to form cruciform subassemblies, thereby increasing the stability and rigidity of the assembly. The spacing and orientation of the slots and magnets and the shapes of the structural components are coordinated so as to give one the option of keeping the center-to-center spacing of adjacent ferromagnetic balls substantially constant while at the same time drawing on one's imagination and creativity in building constructions having a broad variety of sizes, shapes, and/or configurations.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, reference is made to the following detailed description of various exemplary embodiments considered in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective top view of a structural component constructed in accordance with a first exemplary embodiment of the present invention;

FIG. 2 is a side elevational view of the structural component of FIG. 1;

FIG. 3 is an edge elevational view of the structural component of FIG. 1 taken along view line 3-3 shown in FIG. 2;

FIG. 4 is a sectional view of the structural component of FIG. 1 taken along the section line 4-4 shown in FIG. 2;

FIG. 5 is a sectional view of the structural component of FIG. 1 taken along section line 5-5 shown in FIG. 3;

FIG. 6 is a perspective top view of a construction made from multiple instances of the structural component of FIG. 1 assembled together using spherical connecting elements;

FIG. 7 is a top plan view of the construction depicted in FIG. 6;

FIG. 8 is a sectional view of the construction of FIG. 6 taken along the section line 8-8 shown in FIG. 7;

FIG. 9 is a sectional view of the construction of FIG. 6 taken along the section line 9-9 shown in FIG. 7;

FIG. 10 is a sectional view of an alternative embodiment of the structural component of FIG. 1 taken along the equivalent of section line 5-5 shown in FIG. 3;

FIG. 11 is a side elevational view of a structural component constructed in accordance with a second exemplary embodiment of the present invention;

FIG. 12 is a perspective top view of two instances of the structural component of FIG. 11 in the process of being assembled together;

FIG. 13 is a perspective top view of a cruciform subassembly formed as a result of the structural components of FIG. 12 being assembled together in the manner shown in FIG. 12;

FIG. 14 is a top plan view of a construction made from multiple instances of the cruciform subassembly of FIG. 13 assembled together using spherical connecting elements;

FIG. 15 is a perspective top view of a structural component constructed in accordance with a third exemplary embodiment of the present invention;

FIG. 16 is an edge elevational view of the structural component of FIG. 15;

FIGS. 17-18 are perspective top views of additional structural components constructed in accordance with the third exemplary embodiment of the present invention;

FIG. 19 is a top plan view of a construction made from multiple instances of the structural components of FIGS. 15-18 assembled together using spherical connecting elements;

FIGS. 20-22 are top views of additional constructions made from multiple instances of the structural components of FIGS. 15, 16, 17 and/or 18 assembled together using spherical connecting elements; and

FIG. 23 is a top plan view of yet another construction made from multiple instances of the structural component of FIGS. 15-16 assembled together using a spherical connecting element.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1-3, there is shown a structural component 10 constructed in accordance with a first embodiment of the present invention. The structural component 10 includes a body 12, which is substantially planar in configuration, and is substantially square in general peripheral shape. The body 12 of the structural component 10 includes a first major surface 14, a second major surface 16 opposite and substantially parallel to the first major surface 14, and a peripheral edge surface 18 disposed between the first and second major surfaces 14, 16. The peripheral edge surface 18 includes four side edges 20. An interconnection element 22 is disposed in each such side edge 20, located substantially at the midpoint along the respective length thereof. Though not clearly evident in all of the perspective views, the exposed surface of the magnet is preferably slightly recessed from its surrounding surface if he magnet is intended to attract a non-planer (e.g., spherical) component of the assembly. In this way the magnetic attraction pulls the non-planar component into engagement with the surrounding surface.

Referring to FIGS. 1-5, each interconnection element 22 consists of a recess 24 formed in the associated side edge 20, which is otherwise substantially linear in shape. The recess includes a substantially spherical side wall 26 having a function to be explained hereinafter. The centerpoint C of the radius R defining each spherical side wall 26 is substantially coplanar with the body 12 of the structural component 10 and centered above the associated side edge 20. Although the preferred embodiment includes a spherical side wall 26, in an alternative embodiment side wall 26 includes a cylindrical side wall.

Each interconnection element 22 further includes a pocket 28 formed within the body 12, a peripheral flange 30 formed in the edge surface 18 (i.e., in the spherical side wall 26) and defining an opening 32 to the pocket 28, and a magnet 34 contained within the pocket 28 and having an outward-facing magnetic surface 36 adjacent to and coextensive with the opening 32 to the pocket 28 near the edge surface 18. The peripheral flange 30 includes a substantially planar inner rim 38 adjacent the magnetic surface 36 for retaining the magnet 34 within the pocket 28, an outer edge 40 having a shape consistent with the locally spherical shape of the adjacent edge surface 18, and a beveled surface 42 disposed between the inner rim 38 and the outer edge 40.

In operation, multiple instances of the structural component 10 can be assembled together with ferromagnetic balls to form stable constructions. Referring to FIGS. 6-7, an exemplary construction 44 is shown including multiple instances of the structural component 10, as well as numerous ferromagnetic balls 46 magnetically connected to, and disposed between, the magnets 34 (see FIGS. 4-6) of the interconnection elements 22 of the structural components 10. The diameters D of the ferromagnetic balls 46 are substantially equivalent, each such diameter preferably being held to within a tight mechanical tolerance of a common value. As may be seen with reference to FIG. 2, the structural component 10 includes two substantially similar dimensions, such dimensions preferably being held to within a tight mechanical tolerance of a common value, and such value being represented by the designation “B”. The “B” designations represent the substantially similar distances as measured between the outward-facing magnetic surfaces 36 of axially-aligned magnets 34 (see FIGS. 2, 4 and 5) contained in the structural component 10. It will therefore be apparent that close coordination is achieved between and among the positions, configurations, and orientations of the interconnecting elements associated with such structural components. One salutary effect of this close coordination is that the many ferromagnetic balls 46 contained in the construction 44 are caused to be arranged in a regular array 48 having consistent regular horizontal and vertical spacing, which is not only aesthetically pleasing to the eye, but is also conducive to producing constructions of various scales with consistent precision and stability. This also serves to spark the imagination and creativity of one who uses such structural components to build constructions, since there are very few limits on the shape or configuration of constructions that may be built in accordance with the present invention.

Referring to FIGS. 8-9, and as mentioned above, the ferromagnetic balls 46 connect with and/or interconnect the structural components 10 of the construction 44. More particularly, a ferromagnetic ball 46 can be placed in magnetic contact with the magnetic surface 36 of the magnet 34 of the interconnection element 22 of the structural component 10. The size and shape of the recess 24, and specifically of the spherical side wall 26, is such that the spherical side wall 26 is placed in surface-to-surface spherical contact with the ferromagnetic ball 46 while the ball 46 is simultaneously in contact with the magnetic surface 36. Thus the ferromagnetic ball 46 is not only allowed to remain in secure magnetic contact with the structural component 10, it is also kept in a constant position and orientation with respect to the interconnection element 22 by the “seat” provided by the spherical side wall 26. In an alternative embodiment, the side wall 26 is a cylindrical side wall that aligns with another cylindrical side wall 26 for supporting ferromagnetic ball 46. However, the “seat” provided by the spherical side wall 26 is preferred to the cylindrical side wall.

It should be appreciated that numerous advantages are provided by the structural component 10 and/or by constructions (such as the construction 44) containing such structural components in assembly with ferromagnetic balls 46 in accordance with the foregoing description. The consistent spacing between the opposite magnetic surfaces of axially-aligned magnets of such a structural component, designated by “B”, ensures consistent center-to-center distances, designated by “A”, between adjacent ferromagnetic balls 44 in the array (e.g., the array 48 of FIGS. 6-7). In addition, disassembly and reassembly can be accomplished with great speed.

It should also be noted that the structural component 10 can have numerous modifications and/or variations consistent with the first embodiment of the present invention. For example, the structural component 10 can be modified to describe a general planar shape other than that of a square, or even other than that of a polygon. Also, a generally polygonal shape of the structural component 10 can be altered with one or more curved edge surfaces as desired. For another example, one or more of the interconnecting elements of such a structural component can be positioned on an edge surface other than at the midpoint along the length thereof so as not to coincide with the standard spacing of the array formed by the ferromagnetic balls. The same result can be achieved by providing an edge surface that diverges in shape or angle of extension from a more regular (e.g., straight and perpendicular) arrangement. For still another example, and as shown in FIG. 10, an alternative structural component 50, similar to the structural component 10 except as indicated below, can be used in addition to and/or as a replacement for the structural component 10. More particularly, the structural component 50 has a body 52 formed from two or more parts 54 (e.g., consisting of translucent and/or colored molded plastic) which are substantially hollow and are assembled together, e.g., via ultrasonic welding to form the body 52. Two or more of the molded plastic parts 54 contain molded wall sections 56 which can be combined to form pockets 58 to hold magnets (not shown) as part of one or more interconnection elements 60 otherwise similar to the interconnection element 22 of the structural component 10. The magnets (not shown) can be captured in the pockets 58 during body assembly. For a further example, magnets of different types, sizes and shapes can be used, it being recognized that rare-earth magnets in particular can provide exceptional strength per unit volume, and that a cylindrically-shaped magnet can provide excellent dimensional and orientational uniformity in the assembled structural component. In still another example of a modification, the magnets associated with the above-described interconnection elements can be embedded without retaining flanges in the bodies of the structural components.

Additional exemplary embodiments of the present invention are illustrated in FIGS. 11-23. Elements illustrated in FIGS. 11-23 which correspond substantially to the elements described above with reference to FIGS. 1-10 have been designated by corresponding reference numerals increased by one or more increments of one thousand. The embodiments of the present invention shown in FIGS. 11-23 operate and are constructed in manners consistent with the foregoing description of the first embodiment of the invention, unless it is stated otherwise.

Referring to FIG. 11, there is shown a structural component 1010 constructed in accordance with a second embodiment of the present invention. The structural component 1010 includes three interconnection elements 1022, each of which is similar to the interconnection element 22, and an interconnection element 1062. The interconnection element 1062 is located at the midpoint along the length of the associated side edge 1020, and includes a recess 1064 and a spherical side wall 1066 similar to the recess 24 and the spherical side wall 26, respectively, except in that the interconnection element 1062 also includes a slot 1068 formed in the spherical side wall 1066. The slot 1068 includes side walls 1070 oriented substantially parallel to each other, but perpendicular to the linear portion of the associated side edge 1020. A substantially planar bottom wall 1072 is oriented perpendicular to the side walls 1070 and parallel to the linear portion of the associated side edge 1020. Similar to the interconnection element 22, the interconnection element 1062 includes a pocket 1074 formed within the body 1012, an opening 1076 to the pocket 1074, and a magnet 1078 contained within the pocket 1074 and having an outward-facing magnetic surface 1080 adjacent to and coextensive with the opening 1078 to the pocket 1074 near the edge surface 1018.

In operation, the structural component 1010 can be assembled together with ferromagnetic balls to form stable constructions, which can include a combination of one or more cruciform subassemblies formed when two of the structural components 1010 are assembled together in an interlocking fashion. For example, and as shown in FIGS. 12-13, two instances of the structural component 1010 can be oriented such that their respective slots 1068 face each other, after which the structural components 1010 can be merged to the limit allowed by their respective slot bottom walls 1072. Each of the slots 1068 terminates (i.e., each of the slot bottom walls 1072 fall) at approximately the midpoint of the height of its respective structural component 1010, such that when two structural components 1010 are merged as just described, the adjacent side edges 1020 of the two structural components 1010 become substantially coplanar, and the adjacent spherical side walls 1026, 1066 become spherically aligned. The dimensional width of each slot 1068 closely tracks the thickness of its respective structural component 1010 so as to produce a frictional fit between the two structural components 1010 when the same are merged as described above. Further, the polarities or magnetic domains of the magnets 1078 associated with the respective slots 1068 can be coordinated (e.g., to ensure the north pole of one such magnet 1078 faces the south pole of the other such magnet 1078) so as to produce magnetic attraction between the two structural components 1010. As shown in FIGS. 13 and 14, the above-described merging of a pair of structural components 1010 forms a precisely-configured three-dimensional cruciform subassembly 1082, multiple instances of which can be incorporated into a larger construction for any number of purposes, including contributing structural stability to the assembly.

Referring to FIG. 14, a construction 1084 is shown including multiple instances of the structural component 1010 arranged in the form of cruciform subassemblies 1082, as well as numerous ferromagnetic balls 1046 magnetically connected to, and disposed between, the magnets 1034 (see FIG. 11) of the interconnection elements 1022 of the structural components 1010. As shown in FIG. 14, constant center-to-center spacing “A” between ferromagnetic balls 1046 is maintained in the same manner as described above with reference to FIGS. 6-7.

Referring to FIGS. 15-16, there is shown a structural component 2010 constructed in accordance with a third embodiment of the present invention. The structural component 2010 includes four interconnection elements 2022, each of which is similar to the interconnection element 22, except that each of the side edges 2020 in which the interconnection elements 2022 are formed includes a taper 2086 comprising slanted surfaces 2088 adjacent both major surfaces 2014, 2016 of the structural component 2010. The tapers 2086 and the associated slanted surfaces 2088 reduce the peripheral thicknesses of the side edges 2020 and serve other functions as will be described more fully hereinafter.

Additional structural components constructed in accordance with the third embodiment of the present invention are shown in FIGS. 17 and 18, including a structural component 2090 shown in FIG. 17 and a structural component 2092 shown in FIG. 18.

As shown in FIG. 17, the structural component 2090 is in the general shape of an isosceles triangle. More particularly, the structural component 2090 includes two side edges 2094 substantially similar to the side edges 2020 of the structural component 2010. Such similarity extends to the presence of interconnection elements 2096 located at the midpoint of each such side edge 2094 that are substantially similar to the interconnection elements 2022, and to the fact that the otherwise linear shapes of the two side edges 2094 form a right angle with respect to each other. The structural component 2096 further includes a substantially linear diagonal side edge 2098 disposed between ends 2100, 2102 of the side edges 2094. The diagonal side edge 2098 includes a taper 2086 and associated slanted surfaces 2088. An interconnection element 2104 is disposed on the diagonal side edge 2098, located substantially at the midpoint along the length thereof. The interconnection element 2104 is similar to the interconnection elements 2096, but contains no magnet or magnet-holding pocket of its own. Instead, nearby magnets 2034 of two interconnection elements 2096 together provide the magnetic attraction by which the interconnection element 2104 functions.

As shown in FIG. 18, the structural component 2092 is in the general shape of an equilateral triangle. More particularly, the structural component 2092 includes three side edges 2106 which are equivalent in length and therefore form three substantially equivalent angles (i.e., measuring approximately sixty degrees each). With the exception of a slightly shorter length, the side edges 2106 are substantially similar to the side edges 2020 of the structural component 2010. Such similarity extends to the presence of interconnection elements 2108 which are located at the midpoint of each such side edge 2106 and which are substantially similar to the interconnection elements 2022.

In operation, one or more instances of the structural components 2010, 2090, 2092 can be assembled together with ferromagnetic balls to form stable constructions. For example, such constructions can include constructions 2110, 2112, 2114, 2116, 2118 formed with ferromagnetic balls 2046 as shown in FIGS. 19-23, respectively.

As shown in FIG. 19, the configuration of the construction 2110 is substantially planar, and multiple instances of the structural components 2010, 2090, 2092 have been interconnected in a creative fashion resembling a mosaic or tile floor. FIGS. 20, 21 and 22 show the structural components 2010, 2090, 2092 combined to form the constructions 2112, 2114, 2116, each of which extends in three dimensions. The construction 2118 shown in FIG. 23 also extends in three dimensions, and more particularly illustrates the facility with which multiple instances of the structural component 2010 can be connected to the same ferromagnetic ball 2046 (e.g., with 60 degree spacing therebetween around the perimeter of the ferromagnetic ball 2046). Such facility is due at least in part to the narrow profile of the side edges 2020 of the structural component 2010, which in turn is produced by the slanted surfaces 2088 of the tapers 2086 thereof. As shown in FIGS. 19-22, standard center-to-center spacing (i.e., indicated by “A”) between adjacent ferromagnetic balls can be maintained, or if desired, alternative arrangements, such as a hexagonal arrangement 2120 (see FIG. 19) or a pyramidal arrangement 2122 (see FIG. 22), can be produced.

It will be understood that the embodiments of the present invention described herein are merely exemplary and that a person skilled in the art may make many variations and modifications without departing from the spirit and scope of the invention. For example, the magnet 1078 of the interconnecting element 1068 may be removed and the frictional fit between the two structural components 1010 relied upon to keep such structural components together as part of the cruciform subassembly 1082. Additionally, other magnetic domains (i.e., north/south polarity arrangements) than those shown in FIGS. 2 and 11 may be provided with respect to the magnets 34, 1034, 1078 of the structural components 10, 1010. All such variations and modifications, including those discussed above, are therefore intended to be included within the scope of the present invention. Further, this application is related to co-pending U.S. patent application Ser. No. ______, entitled Magnetic Toy Construction Modules with Corner-Adjacent Magnets by Kowalski et al., filed ______, which is herein incorporated by reference in its entirety. 

1. A planar body, comprising: a first major surface; a second major surface opposite and substantially parallel to the first major surface; a peripheral edge surface disposed between and substantially perpendicular to the first and second major surfaces, the peripheral edge surface including a plurality of side edges; a slot formed in a first side edge of the plurality of side edges; a first recess formed in the first side edge, the first recess including a substantially curved side wall; and a first pocket formed within the first side edge adjacent the slot, the first pocket having a first magnet with an outward-facing magnetic surface disposed therein.
 2. The planar body of claim 1, wherein the outward-facing magnetic surface is recessed from an outer surface of the peripheral edge surface to form a seat.
 3. The planar body of claim 1, wherein the curved side wall is a spherical side wall.
 4. The planar body of claim 1, wherein the planar body is in the general shape of a triangle.
 5. The planar body of claim 1, wherein the planar body is in the general shape of a rectangle.
 6. The planar body of claim 1, further comprising a second pocket formed adjacent the slot, the second pocket having a second magnet with an outward-facing magnetic surface disposed therein.
 7. A three-dimensional assembly, comprising: a plurality of substantially planar bodies, each substantially planar body having a generally polygonal shape including a first major surface, a second major surface opposite and substantially parallel to the first major surface, a peripheral edge surface disposed between and substantially perpendicular to the first and second major surfaces, the peripheral edge surface including a plurality of side edges, a slot formed in a first side edge of the plurality of side edges, a first recess formed in the first side edge, the first recess including a substantially curved side wall, and a first pocket formed within the first side edge adjacent the slot, the first pocket having a first magnet with an outward-facing magnetic surface disposed therein; and a first planar body and a second planar body of the plurality of substantially planar bodies interlocked such that the slot of first planar body engages the slot of the second planar body and the first magnet of the first planar body magnetically bonds to the first magnet of the second planar body, the first recess of the first planar body aligning with the first recess of the second planar body to form a first seat.
 8. The three-dimensional assembly of claim 7, further comprising: a ferromagnetic ball; and a third planar body and a fourth planar body of the plurality of substantially planar bodies interlocked such that the slot of third planar body engages the slot of the fourth planar body and the first magnet of the third planar body magnetically bonds to the first magnet of the fourth planar body, the first recess of the third planar body aligning with the first recess of the fourth planar body to form a second seat, wherein the third planar body and the second planar body are coupled such that the first seat and the second seat align to form a third seat for the ferromagnetic ball, the ferromagnetic ball magnetically bonds to the first magnet of the third planar body and to the first magnet of the second planar body.
 9. The three-dimensional assembly of claim 8, further comprising: a second magnet adjacent the first seat; and a third magnet adjacent the second seat, wherein the second magnet magnetically bonds the ferromagnetic ball to the second planar body and the third magnet magnetically bonds the ferromagnetic ball to the third planar body.
 10. The three-dimensional assembly of claim 8, wherein the first magnet, second magnet and third magnet are each recessed from the peripheral edge.
 11. The three-dimensional assembly of claim 7, wherein the substantially curved side wall is a spherical side wall.
 12. The three-dimensional assembly of claim 7, wherein each substantially planar body of the plurality of substantially planar bodies further includes a second recess formed in a second side edge of the plurality of side edges, the recess including a substantially curved side wall; and a second pocket formed within the second side edge adjacent the second recess, the second pocket having a second magnet with an outward-facing magnetic surface disposed therein, wherein the second recess of the first planar body and the second recess of the second planar body align to form a second seat.
 13. A three-dimensional assembly, comprising: a plurality of substantially planar bodies, each substantially planar body having a generally polygonal shape including a first major surface, a second major surface opposite and substantially parallel to the first major surface, a peripheral edge surface disposed between and substantially perpendicular to the first and second major surfaces, a recess formed in the peripheral edge surface, the recess including a substantially curved side wall, and a first pocket formed within the peripheral edge surface adjacent the recess, the first pocket having a first magnet with an outward-facing magnetic surface disposed therein; a ferromagnetic ball; and a first planar body and a second planar body of the plurality of substantially planar bodies coupled such that the first recess of the first planar body aligns with the first recess of the second planar body to form a seat for the ferromagnetic ball, the ferromagnetic ball magnetically bonding to the first magnet of the first planer body and the first magnet of the second planer body.
 14. The three-dimensional assembly of claim 13, wherein each planar body of the plurality of substantially planar bodies further comprises a second pocket formed within the peripheral edge surface adjacent the recess, the second pocket having a second magnet with an outward-facing magnetic surface disposed therein, the ferromagnetic ball magnetically bonding to the second magnet of the first planer body and the second magnet of the second planer body.
 15. The three-dimensional assembly of claim 13, wherein the outward-facing magnetic surface of the first magnet is recessed from an outer surface of the peripheral edge.
 16. The three-dimensional assembly of claim 13, wherein the curved side wall is a spherical side wall.
 17. The three-dimensional assembly of claim 13, wherein each of the first and second planar bodies is in the general shape of a triangle.
 18. The three-dimensional assembly of claim 13, wherein each of the first and second planar bodies is in the general shape of a rectangle.
 19. The three-dimensional assembly of claim 13, wherein the recess is formed at a midpoint along a length of a side of a plurality of sides of the peripheral edge. 